iTunes privacy hole shares library content with world+dog

A technology researcher has unearthed a privacy hole in Apple's iTunes Store that makes it easy for unauthorized people to learn what music, videos and apps you've acquired from the online bazaar.

The technique, which is described in a recent post by Andrew McAfee, exploits design weaknesses in a feature of the online store that allows one customer to send gifts to another iTunes customer. By creating a list of songs, videos or apps and telling iTunes the email address of the intended recipient, you can find out whether the person already has acquired the title from Apple.

“This is done with good intentions – to keep users from gifting music that the recipient already has – but the implementation of this feature opens up privacy concerns: if the check reveals duplicates, iTunes tells the gifter about one of them,” McAfee writes. “The application presents this information to [the snoop] in red ink, before he has to sign in to his account, present credit card information, or take any other steps.”

What's more, the disclosure happens without notifying or getting permission from the recipient. All that's required is the email address the person uses with her iTunes account. People who exploit the weakness to spy on others need not sign into an account, provide a credit card number or take other steps, McAfee says.

No doubt, music purchases aren't the most sensitive of lists. Plenty of people are more than happy to share their music tastes with anyone who will listen. But as McAfee points out, the Video Privacy Protection Act imposes federal penalties on any person engaged in the business of renting, selling or delivering a “video tape” who publishes information about a customer's viewing habits.

Apple's response when users are given titles they've already acquired as gifts is in stark contrast to the way Amazon handles Amazon Kindle gifts that the recipient already owns. According to McAfee, Amazon lets the purchase go through, but instead of sending the receiver a title she already owns, gives her credit for the title instead.

“To put it mildly, this seems like a better approach to me,” McAfee says. ®